Mishnah Bekhorot 2:1: If one buys an unborn cow fetus from a non-Jew, sells [an unborn cow fetus] to [a non-Jew] even though one does not have permission to, has a partnership with [a non-Jew], receives [an unborn cow fetus] from [a non-Jew], or gives [an unborn cow fetus] to [a non-Jew], [the unborn cow fetus] is exempt from [the obligations of] the firstborn. As it is written (Numbers 3:13): "in Israel", but not by others. Priests and Levites are obligated, for they were not exempted from [the obligations of] the firstborn of a pure kosher animal, (they were only exempted) from redemption the firstborn son and [the obligations of] the firstborn of a donkey.

הלוקח עבר פרתו של נכרי, והמוכר לו אף על פי שאינו רשאי, המשתתף לו, והמקבל ממנו, והנותן לו בקבלה, פטור מן הבכורה, שנאמר (במדבר ג:יג), בישראל, אבל לא באחרים. כהנים ולוים חיבין. לא נפטרו מבכור בהמה טהורה, [ולא נפטרו] אלא מפדיון הבן ומפטר חמור.

Mishnah Bekhorot 2:2:If the blemishes of consecrated [animals] precede their consecrations, and they are redeemed, they are subject to [the obligations of] the firstborn and the [priestly] gifts. They leave [their consecrated status] to become unconsecrated and [thus] may be shorn and worked. Their offspring and their milk [from] after they have been redeemed are permitted. If one slaughtered them outside [the Temple courtyard] he is not liable. They do not make [their] replacement [sacred]. If they die they may be redeemed, except for firstborn and tithe [animals].

כל הקדשים שקדם מום קבוע להקדשן, ונפדו, חיבים בבכורה ובמתנות, ויוצאין לחלין לגזז ולהעבד, וולדן וחלבן מתר לאחר פדיונן, והשוחטן בחוץ פטור, ואין עושים תמורה, ואם מתו יפדו, חוץ מן הבכור ומן המעשר.